We are investigating the cellular basis of integration in the nerve plexus of Notoplana acticola, a flatworm which has a nerve plexus that is amenable to dissection and exposure. The nerve plexus contains reflexes which can initiate locomotion in the animal but there is also a central control from the brain which affects coordination between the two sides of the plexus. The system has been chosen as one can see and record directly from strands of the plexus and also record intracellularly from cells in the brain. Besides having a convenient plexiform nervous system, the flatworms are also the most primitive organisms to possess a brain as well as being one of the last major phyla to be investigated electrophysiologically. We propose to isolate sites in the plexus involved with locomotion using suction electrodes recording from known positions along the plexus and isolate cells in the brain involved with coordination of these patterns using microlesions in the cerebral ganglion. Cells which appear to be important in the coordination of locomotion will receive intensive investigation using standard intracellular recording and stimulating techniques and their effects on the peripheral components monitored simultaneously. The cells involved will be stained with cobalt or procyon dyes and their connections with the rest of the anatomical nervous system determined. Eventually we hope to be able to understand how coordination between the central brain and peripheral plexus at the cell level results in a specific behavior pattern.